1. Field of the Invention
The present invention relates to a twin-clutch manual transmission which includes two clutches respectively connected by shafts to two groups of transmission gear sets, in which smooth gearshifts are achieved by alternately disengaging one of the clutches while engaging the other to change the gear set engaged.
2. Description of Related Art
Japanese Patent Application Laid-open Publication no. 8-320054 discloses a twin-clutch manual transmission for a front engine and front wheel drive vehicle (FF-vehicle), which includes first and second input shafts adapted to be selectively and drivably connected for receiving an engine power output through respective clutches. The second input shaft is hollow and rotatably supported on the first input shaft. The first input shaft protrudes outward from a rear end of the second input shaft at a position remote from the engine. Gear sets of even-numbered gear range group is disposed between a rear end protruding portion of the first input shaft and the counter shaft which is placed in parallel to the first and second input shafts, for suitably providing selective power transfer. Further, gear sets of odd-numbered gear range group are disposed between the second input shaft and the counter shaft for suitably providing selective power transfer, whereby the engine power output resulting from gearshift depending on a selected gear range can be extracted from a front end of the counter shaft in a radial direction at a position closer to the engine.
With such a twin-clutch manual transmission, even when one gear range of one of the groups is selected with the associated clutch being engaged, next gear range of the other group can be pre-selected with the associated clutch therewith being disengaged. A gearshift can be realized by disengaging the clutch associated with the one gear range, while engaging the clutch associated with the next gear range of the other group, that is, upon a so-called clutch changeover control. By alternately selecting an intended gear range between the gear range groups, it is possible to perform an automatic power transmission even with a manual transmission.